JPH0248966B2 - JIKIKIROKUTAI * SONOSEIZOHONARABINISEIZOSOCHI - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a magnetic recording medium suitable for recording using a ring head, a method for manufacturing the same, and an apparatus for manufacturing the same. When a conventional magnetic recording medium with a perpendicular magnetization film is used for recording with a ring head, the ring head generates a semicircular magnetic field as shown in Figure 1, so its high-density recording characteristics are lower than that of a perpendicular head. It has the disadvantage of poor reproduction output. That is, in a ring head, the magnetic field component in the perpendicular direction is strong on the surface side of the perpendicularly magnetized film, but the magnetic field component in the parallel direction is large on the side away from the head, that is, inside the film or near the interface with the substrate. Therefore, the inside of the film and the vicinity of the interface with the substrate are not sufficiently magnetized. this is,
This is because the parallel direction is a difficult magnetization direction in a completely perpendicularly magnetized film. As a result of various studies on this point, the present invention has improved this and has a completely perpendicular magnetization film (Hc⊥/Hc>1,
Mr
A magnetic recording body comprising a quasi-perpendicular magnetization film that satisfies the following conditions on a non-magnetic substrate. Hc⊥／Hc≧1 Hc≧400θe 1≧Mr⊥／Mr≧0.5 where Hc⊥: Coercive force perpendicular to the film surface Hc: Parallel to the film surface in the traveling direction during recording and reproduction Coercive force Mr⊥: Residual magnetization in the direction perpendicular to the film surface Mr: Residual magnetization in the direction parallel to the film surface during recording and reproduction The quasi-perpendicular magnetization of the above magnetic recording body of the present invention using a ring head Figure 2 shows how the film is magnetized.The film a has magnetic anisotropy in the vertical direction and has a large coercive force in the perpendicular direction, so near the film surface where the magnetic field component in the perpendicular direction is large, As in the case of using a conventional completely perpendicularly magnetized film, it is magnetized vertically, and inside the film and near the interface with the substrate b, it is magnetized along the horizontal magnetic field component of the semicircular magnetic field generated by the ring head c. Since it is magnetized, the demagnetizing field inside the film and near the interface with the substrate _a2 is reduced, and therefore high reproduction output and high recording density characteristics can be obtained. Thus, the quasi-perpendicularly magnetized film of the present invention can be magnetized along the magnetic field generated by the ring head. In particular, a large demagnetizing field is generated in the perpendicular direction on the film surface, so Hc⊥/
The condition that Hc>1 is essential. In addition to the above magnetic properties, if the direction of magnetic anisotropy in the film plane matches the recording direction, the self-demagnetizing effect can be further reduced, further improving high-density recording properties and reproduction output. be able to. In the case of a magnetic tape, this direction is the longitudinal direction, and in the case of a disk, it is the circumferential direction. In this quasi-perpendicularly magnetized film, the magnetic anisotropy of the entire film is in the perpendicular direction, as can be seen from the above characteristic conditions, and furthermore, the magnetic property is that the anisotropy on the film surface coincides with the recording direction. It's summery. First,
The inventors created a (Fe, Co, Ni)-O-based perpendicularly magnetized film by depositing Fe, Co, Ni, or their alloys on a non-heated non-magnetic substrate surface in a vacuum atmosphere with O ₂ gas introduced. Although a method of manufacturing by almost perpendicular incident deposition has been proposed, it has been found that the above-mentioned quasi-perpendicularly magnetized film can be manufactured by a method substantially similar to this method. That is, in the above manufacturing method, it is sufficient to reduce the perpendicular magnetism to some extent,
For example, it has been found that it can be obtained by performing similar almost vertical deposition on a nonmagnetic substrate heated and maintained at a temperature in the range of 100 to 400°C. In other words, when a mixture of non-ferromagnetic oxide particles and metal ferromagnetic particles adheres to a heated substrate, the heat causes the metal ferromagnetic particles to become coarser, increasing the coercive force and at the same time disrupting the vertical alignment. It has been found that the magnetic anisotropy is reduced, resulting in a quasi-perpendicularly magnetized film of the present invention. When the temperature significantly exceeds 400°C, the coercive force decreases because the particle size becomes too large. The quasi-perpendicular magnetization film can be manufactured by any of the vacuum evaporation method, ion plating method, and sputtering method. Next, an embodiment of the method of manufacturing a magnetic recording medium having the quasi-perpendicular magnetization film according to the present invention will be described in detail with reference to FIG. 3, together with a typical manufacturing apparatus. Reference numeral 1 denotes a vacuum processing container having an exhaust port 2 connected to a vacuum pump. Inside the container 1, a heated rotating metallic cylinder 3 is placed at the center, and a tape-shaped non-magnetic material is placed on both sides above the container. An unwinding roller 4 and a winding roller 5 are provided for the base material a, and the tape-shaped non-magnetic base material b is spanned between these 4 and 5 with it being attached to the circumferential surface of the cylindrical body 3 in the middle thereof, This was made to run at a predetermined speed in the direction of the arrow. An electron beam evaporation source 6 is provided directly below the cylindrical body 3, a small gap 7 is provided near the lower end surface of the cylindrical body 3, and adhesion prevention plates 8 and 9 are provided on both sides of the gap 7. One deposition prevention plate A is installed horizontally so that it can be moved left and right in the drawing, and the evaporated atoms of material B made of Fe, Co, Ni, or alloys thereof from the evaporation source 6 are deposited at an incident angle of θ ₁ . It is now possible to adjust the settings as appropriate. The angle of incidence θ ₂ with respect to one of the adhesion prevention plates 9 can also be made freely movable as required. Further, an O ₂ introduction pipe 10 that opens into the evaporation region so that O ₂ can be blown out is provided to penetrate the wall of the container 1 in an airtight manner. Use such a device and operate it as follows. That is, the non-magnetic substrate a ₂ is moved in the direction of the arrow and brought into contact with the outer peripheral surface of the cylindrical body 3 which has been heated from the inside to, for example, 300°C by any means, and the substrate b is heated to 300°C. , ferromagnetic metal evaporated atoms rising from below through the gap 7 are deposited on the surface a of the heating substrate at an almost perpendicular incidence angle while passing through the lower end surface of the cylindrical body 3, and the quasi-perpendicularly magnetized film a After it is formed, it is wound up on the roller 5. As a comparison test, θ ₁ was set to 0° and 30°.
We talked about types. θ ₂ was kept constant at 30°. In-plane magnetic anisotropy of the created magnetized film is not observed when θ ₁ is 0°, but when θ ₁ is 30°, in-plane magnetic anisotropy occurs in the longitudinal direction of the tape. did. This is because the direction of the nucleus that initially appears on the base material surface determines the direction of subsequent crystal growth; when θ ₁ is 0°, the crystal grows vertically, but when θ ₁ is 30°, the crystal grows vertically. This is considered to be because crystal growth occurs with a slight inclination in the longitudinal direction in the case of .degree. On the other hand, due to the heat of the heated base material, the particles become coarser and their vertical alignment is disrupted, thereby ensuring the production of the quasi-perpendicularly magnetized film of the present invention. Using the _above apparatus, various compositions of Fe, Co, Ni, and their alloys, and these various metals and O
We created various magnetized films with different compositions of atoms and measured their various magnetic properties. The results are shown in FIGS. 4 to 15. From these results, it can be seen that the quasi-perpendicularly magnetized film of the present invention having the above magnetic property conditions is (Fe _x Co _y
Ni _z ) _1-n On the composition represented by _n , 0≦x≦
0.05, 0≦z≦0.40 (x+y+z=1), 0.10
In the range of ≦m≦0.40 and the above composition, 0.40≦x≦1.0, 0≦z≦0.25 (however, x+y+
z=1), and 0.10≦m≦0.40. Next, the recording and reproducing characteristics of the sample having the quasi-perpendicular magnetization film of the present invention were measured. For comparison, measurements were taken on a sample with a completely perpendicular magnetization film and a sample with a completely obliquely deposited magnetization film. All film thicknesses were kept constant at 2000 Å. The results are shown in the table below.

[Table] Hc indicates the in-plane coercive force measured in the length direction of the tape, ^* Hc indicates the in-plane coercive force measured in the width direction of the tape. Samples No. 1 and 3 were created with the incident angle θ ₁ set to 0°, and sample No. 2 was created with the incident angle θ ₁ set to 0°.
Hc (θe) or ^* Hc (θe) for the one created at 30°
It has a characteristic that the direction of magnetic anisotropy within the film plane clearly matches the direction in which it travels during recording and reproduction. Sample No. 4 has an Hc value of 300θe
It is inappropriate. Sample No. 5 has Mr⊥/Mr of 1.5 and is a perfectly perpendicularly magnetized film. Sample No. 6 is Hc⊥／
With Hc=0.7, it is a perfectly diagonally magnetized film. The playback output of these sample magnetic tapes having a width of 1/4 inch was measured using a measuring device modified from a reel-to-reel audio deck. The tape running speed during measurement was 4.8 cm/sec. Recording was performed using a sine wave to determine the optimum recording current at each frequency. The results are shown in FIG. From this figure, it can be seen that excellent recording and reproducing characteristics are obtained in the invention sample Nos. 1 to 3. In this way, according to the present invention, Hc⊥/
Hc≧1, Hc≧400θe, 1≧MC⊥／Mc≧
By creating a magnetic recording medium with a quasi-perpendicular magnetization film with a magnetic property of 0.5, it is possible to apply it to a ring head and obtain high reproduction output as well as high-density recording. , Co, Ni, or their alloys are deposited on the substrate under the introduction of oxygen.
This has the effect of reliably obtaining a quasi-perpendicular magnetization film based on Co, Ni)-O with high efficiency.

[Brief explanation of drawings]

FIG. 1 is a side view of the operating state of the ring head on the perpendicularly magnetized film, FIG. 2 is a schematic diagram of the operating state of the ring head on the quasi-perpendicular magnetized film of the present invention, and FIG. 3 is a diagram of the apparatus for producing a magnetic recording medium of the present invention. 1
The front view of the example, FIGS. 4 to 15 are magnetic characteristic diagrams of the quasi-perpendicular magnetization film with the (Fe, Co, Ni)O system composition of the present invention, and FIG. 16 is the reproduction output characteristic diagram of each sample. . a... Quasi-perpendicular magnetization film, b... Substrate, 1... Vacuum processing container, 3... Rotating circular body to be heated, 4, 5
...Roller, 6...Evaporation source, 7...Gap, 8,
9... Anti-adhesion plate, θ ₁ , θ ₂ ... Incident angle, 10... O ₂ introduction pipe.

Claims (1)

[Claims] 1. A magnetic recording body comprising a quasi-perpendicular magnetization film that satisfies the following conditions on a non-magnetic substrate. Hc⊥／Hc≧1 Hc≧400θe 1≧Mr⊥／Mr≧0.5 where Hc⊥: Coercive force perpendicular to the film surface Hc: Parallel to the film surface in the traveling direction during recording and reproduction Coercive force Mr⊥: Residual magnetization in the direction perpendicular to the film surface Mr: Residual magnetization in the direction parallel to the film surface and in the running direction during recording and reproduction 2 The quasi-perpendicularly magnetized film is (F _x Co _y Ni _z ) In the composition represented by _1-n O _n , 0≦x≦0.05, 0≦z≦
0.40 (where x+y+z=1) 0.10≦m≦0.40, the magnetic recording body according to claim 1. 3 The quasi-perpendicularly magnetized film has a composition represented by (F _x Co _y Ni _z ) _1-n O _n , 0.40≦x≦1.0, 0≦z
The magnetic recording body according to claim 1, which is in the range of ≦0.25 (where x+y+z=1) and 0.10≦m≦0.40. 4. The magnetic recording body according to claim 1, wherein the quasi-perpendicularly magnetized film has a direction of magnetic anisotropy in the film plane that coincides with a direction in which the film travels during recording and reproduction. 5. While heating the nonmagnetic substrate to a temperature in the range of approximately 100 to 400°C, evaporate one or more magnetic metal atoms such as Fe, Co, Ni atoms, or their alloys almost perpendicularly to the nonmagnetic substrate. A method for producing a magnetic recording material, characterized by simultaneously introducing O ₂ gas and forming a quasi-perpendicular magnetization film. 6 The quasi-perpendicularly magnetized film has a composition represented by (F _x Co _y Ni _z ) _1-n O _n such that 0≦x≦0.05, 0≦z≦
0.40, (where x+y+z=1), 0.10≦m≦0.40, the manufacturing method according to claim 5. 7 The quasi-perpendicularly magnetized film has a composition represented by (Fe _x Co _y Ni _z ) _1-n O _n , 0.40≦x≦1.0, 0≦z
The manufacturing method according to claim 5, wherein the range is ≦0.25 (where x+y+z=1) and 0.10≦m≦0.40. 8. The manufacturing method according to claim 5, wherein the magnetic metal atoms are deposited on the heated substrate at θ ₁ ≧0. 9 A heated cylindrical body to which a non-magnetic base material is to be attached is provided in a vacuum processing container, an evaporation source is provided directly below the evaporation source, and a gap is provided near the lower end surface of the cylindrical body, and adhesion prevention plates are provided on both sides of the cylindrical body. The apparatus for manufacturing a magnetic recording medium further includes an O ₂ introduction hole provided in the vacuum container.